There are several situations in which motorized equipment operates using a supply of volatile fuel such as gasoline or kerosine. When equipment must be operated continuously in order to function properly, there is a need to replenish the supply of fuel quickly, safely, and possibly while the motorized equipment continues to function uninterrupted.
One such example of this kind of situation is when gasoline-powered chain saws are used to cut away brush and foliage during a forest fire, in order to create fire breaks. When a fire-fighter needs to refuel his saw, while acting in a dangerous environment with open flames near at hand, it is extremely crucial that transfer of flammable fuel is conducted in an extremely safe manner. Since gasoline is notoriously volatile, it is extremely important that refueling operations do not allow the release of volatile vapors that can ignite with potentially deadly consequences. Thus there is a need for an apparatus and method that can transfer volatile fluids in a manner which contains flammable vapors from the fuel as it is being transferred to the operating saw.
During operation in firefighting, the fuel tanks in gasoline powered saws such as Stihl saws build up excess pressure due to heat. The fuel tanks and caps in these saws are not capable of venting this excess pressure and when the cap is opened during the fueling process, fuel vapor is released under pressure causing a severe safety hazard. A method of safely relieving the pressure buildup inside the fuel tank before the cap is opened is necessary.
Gasoline powered chainsaws require fuel to operate. Normally fueling is done as follows:
Remove cap on saw gas tank;
Remove seal cap on portable fuel container and install safety spout;
Lift portable fuel container and insert safety spout into chainsaw fuel tank;
When gas starts to overflow from chainsaw tank, remove spout to stop dispensing gasoline;
Reinstall gas cap on chainsaw; and
Remove safety spout from portable fuel container and reinstall seal cap.
This method requires many steps during which vapors from the fuel tank and refueling tank are open to the air and to any sparks or other conditions which may expose these vapors to possible explosion. It is also slow to implement in emergency conditions during which each second may be of crucial importance. The persons using this method may be exposed to considerable stress which may be distracting. Clearly, the simpler the method, the better, while in emergency conditions.
Further disadvantages of this prior art system are that in the course of refueling a hot chainsaw under existing conventional means, the operator has to remove that cap of chainsaw. In many cases, the fuel in the tank of the chainsaw is heated above its boiling point and the tank has become pressurized. When this happens and the cap is opened, it can cause fuel to spray out under pressure which has resulted in numerous reports of serious burns to chainsaw operators and a high risk of injury. This process also releases huge amounts of fuel vapor into the atmosphere. In addition, the conventional fueling method required time consuming process of removing and replacing caps, potential for portable fuel container to be spill fuel if knocked over accidentally, and continuous release of fuel vapor into the atmosphere during the refueling process. Just the release of fuel vapor during the refueling process created a health hazard and risk of fire and injury to the user and surrounding property. In addition, if an operator drops the chainsaw and/or fuel tank during the refueling process (for example if sprayed with fuel, accidentally drop, or emergency occurs) fuel will spill out of both the chainsaw tank and the open portable fuel container.
What is needed is a system and method that will eliminate the need for fuel or vapor to be exposed to the atmosphere during the refueling process. This method of refueling is called a “vapor-tight system”. The basic system works on a fluid exchange principle, instead of a displacement principle. Typically, it is necessary to open both the fuel cap on the saw in addition to the cap on the fuel can, and then pour liquid fuel into the saw exposing both the fuel and vapor to the atmosphere. In contrast a vapor-tight system is sealed. Once the fuel probe and the fuel tank are connected, fluid is simply exchanged from one to the other.
The method disclosed in this invention using this system of components provides a vapor-tight enclosure while provide a quicker, more secure and less dangerous means of transferring fuel under hazardous conditions.
The system used in this method comprises two parts, a receiver that permanently replaces the gas cap on the chainsaw fuel tank and a probe that permanently replaces the seal cap and safety spout normally used on portable fuel containers. In general terms, once the receiver and probe are in place, it is used as follows:                1) Pick up portable fuel container and insert probe into receiver on the chainsaw.        2) While probe is fully engaged into receiver on chainsaw, hold portable fuel container above saw for 10 seconds or until fuel stops flowing. Tank is now full.        
Thus, there is a need for a volatile liquids refueling apparatus which contains volatile fuel vapors during refueling operations and a method of working.
A further need is exhibited in the prior art which can be dangerous to an operator. The prior receiver can be locked or unlocked, and if the receiver is in the “unlocked” position it is possible to accidently open the receiver either with your finger or the bar tool. This would release pressure and cause a potential fuel geyser. The plunger is in the locked position, the user opens the cap and inserts a bar tool “screw driver” to unlock the plunger. While twisting the plunger to unlock it, they press down slightly while turning. As soon as the plunger rotates far enough to unlock it gets depressed slightly. This will open the receiver allowing fuel and vapor “geyser” to escape.
Thus, there is a need for a volatile liquids refueling apparatus which minimizes geysering of volatile fuel vapors during refueling operations, and prevents fuel from escaping accidentally.